CHEMO-AUTOTROPHIC BIOGAS PURIFICATION FOR METHANE ENRICHMENT - MECHANISM AND KINETICS

Off-gas from anaerobic digestion and landfills has significant potential as an alternative energy source. Current technologies to purify off-gas and increase its caloric value have been primarily limited to physicochemical methods. An alternative biological method has been proposed that increases the methane content. Through the use of a chemo-autotrophic methanogen (Methanobacterium thermoautotrophicum), uncoupled methanogenesis techniques and hollow fiber membranes, carbon dioxide is converted to methane and hydrogen sulfide is effectively removed from biological off-gases. This gas stream treatment process improves the quality and caloric value of the biogas. A continuous culture bench-scale system that utilizes hollow fiber membranes was employed to study the process. The gas-phase methane concentrations were found to increase from 60% to 96%.